1. Field of the Invention
This invention relates generally to mattresses, both water mattresses and box spring mattresses, having mattress covers including fabrics with improved stretch and memory characteristics.
2. Discussion of the Prior Art
One of the most persistent problems of the mattress industry has been associated with the stretch characteristics of the fabric used in mattress covers. Since a mattress cover is placed under tension by a person resting on the mattress, eventually the cover begins to stretch from its original flat shape to a hollow shape associated with a person lying on the mattress.
This hollow shape is most noticeable after a person is removed from a bed and the mattress cover tends to define the cavity where he was sleeping. The mattress appears as if the person were still lying on the bed. After the fabric has stretched, it tends to form bunches and wrinkles beneath the sheets of the bed. This is particularly annoying to a person when he returns to the bed and find himself lying on these bunches and wrinkles.
This characteristic of conventional mattress covers is particularly annoying in the case of a waterbed. In order to achieve the significant comfort associated with a flotation system, it is necessary that a person be permitted to sink, at least to some extent, into the watermattress. With conventional watermattress covers, this sinking tends to be inhibited by a fabric which does not stretch as much as it needs to to achieve the full flotation effect.
When the mattress cover lends more support than the water bladder there tends to be a "hammock effect" which reduces the desirable flotation characteristics. Thus, mattress covers associated with waterbeds are called on to stretch even further than those associated with interspring mattresses. It follows that the tendency to develop unsightly body cavities over time is even greater. Of course, in this environment, the adverse effect of the body cavities is even more noticeable.
The fabrics used in mattress covers of the past have included damask and polyester knits. These fabrics have not had any properties for returning to their original shape once they have been stretched. Nor have they had any properties for providing increased stretching in order to inhibit the hammock effect associated with watermattresses. Although these fabrics are fairly heavy and rigid, attempts of the prior art to solve the stretching problem have been directed toward making the fabrics even more rigid. In at least one case, nylon monofiliment has been woven into a half inch mesh which has been glued to the fabric in order to inhibit its stretching. In the case of waterbeds, a more rigid mattress cover has only increased the undesirable hammock effect. There have been no attempts to produce a fabric for mattress covers which accommodate stretching while a person is lying on the bed but has memory characteristics for returning to its original flat shape after a person is removed from the bed.
It has been desirable to include at least one inch of polyurethane foam or polyester fiber in the mattress cover in order to achieve a highly quilted and soft appearance. It has been found, however, that the adverse effects associated with fabric stretching have been even more pronounced when the thicker foams and fibers have been used in the mattress cover.
The industry has suffered from many returned products based on these adverse characteristics of the prior art. Attempts have been made to resew the mattress covers in order to eliminate the wrinkles, but of course this is a timely and aggravating process for both the consumer and the manufacturer.